module OmniAuth
  class Form
    DEFAULT_CSS = File.read(File.expand_path('../form.css', __FILE__))

    attr_accessor :options

    def initialize(options = {})
      options[:title] ||= 'Authentication Info Required'
      options[:header_info] ||= ''
      options[:method] ||= 'post'
      self.options = options

      @html = +'' # unary + string allows it to be mutable if strings are frozen
      @with_custom_button = false
      @footer = nil
      header(options[:title], options[:header_info])
    end

    def self.build(options = {}, &block)
      form = OmniAuth::Form.new(options)
      if block.arity > 0
        yield form
      else
        form.instance_eval(&block)
      end
      form
    end

    def label_field(text, target)
      @html << "\n<label for='#{target}'>#{text}:</label>"
      self
    end

    def input_field(type, name)
      @html << "\n<input type='#{type}' id='#{name}' name='#{name}'/>"
      self
    end

    def text_field(label, name)
      label_field(label, name)
      input_field('text', name)
      self
    end

    def password_field(label, name)
      label_field(label, name)
      input_field('password', name)
      self
    end

    def button(text)
      @with_custom_button = true
      @html << "\n<button type='submit'>#{text}</button>"
    end

    def html(html)
      @html << html
    end

    def fieldset(legend, options = {}, &block)
      @html << "\n<fieldset#{" style='#{options[:style]}'" if options[:style]}#{" id='#{options[:id]}'" if options[:id]}>\n  <legend>#{legend}</legend>\n"
      instance_eval(&block)
      @html << "\n</fieldset>"
      self
    end

    def header(title, header_info)
      @html << <<-HTML
      <!DOCTYPE html>
      <html>
      <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
        <title>#{title}</title>
        #{css}
        #{header_info}
      </head>
      <body>
      <h1>#{title}</h1>
      <form method='#{options[:method]}' #{"action='#{options[:url]}' " if options[:url]}noValidate='noValidate'>
      HTML
      self
    end

    def footer
      return self if @footer

      @html << "\n<button type='submit'>Connect</button>" unless @with_custom_button
      @html << <<-HTML
      </form>
      </body>
      </html>
      HTML
      @footer = true
      self
    end

    def to_html
      footer
      @html
    end

    def to_response
      footer
      Rack::Response.new(@html, 200, 'content-type' => 'text/html').finish
    end

  protected

    def css
      "\n<style type='text/css'>#{OmniAuth.config.form_css}</style>"
    end
  end
end
